Organic cyclophosphine sulfides and selenides and the preparation thereof



United States Patent 3,342,871 ORGANIC CYCLOPHOSPHINE SULFmES ANDSELENIDES AND THE PREPARA- TION THEREOF Ludwig Maier, Zurich,Switzerland, assiguor to Monsanto Company, St. Louis, Mo., a corporationof Delaware No Drawing. Filed Aug. 25, 1965, Ser. No. 482,618 Claimspriority, application Switzerland, Oct. 25, 1962, 12,656/62; Oct. 28,1963, 13,275/63 '13 Claims. (Cl. 260606.5)

ABSTRACT OF THE DISCLOSURE Organic cyclophosphine sulfides andselenides, and a process for making by reacting sulfur or selenium withprimary organophosphines at a temperature suflicient to give offhydrogen sulfide or hydrogen selenide.

I This application is a continuation-in-part of copending applicationSer. No. 406,557, filed Oct. 26, 1964 and copending application Ser. No.318,162, filed Oct. 13, 1963, both now abandoned.

It has been found that organic cyclophosphine sulfides and selenides areobtained by reacting primary organophosphines with elementary sulfur orselenium in a molar ratio of 1:2. The organic cyclophosphine sulfidesand selenides correspond to the formula wherein R signifies analiphatic, cycloaliphatic, araliphatic, aromatic or heterocyclicradical, A is sulfur 0r selenium and n is 3 or 4. The radicals R canpossess ethylenic or acetylenic unsaturations and substituents, such ashalogen, OH, SH, CN, NH CO etc. Moreover, the carbon chains of theradicals R can be interrupted by heteroatoms or heteroatom groups, suchas S, O, N, SO, 80;, NH etc.

Any primary phosphine of the formula RPHg, wherein R has thesignificance defined above, are suitable for the present process. If amixture of primary phosphines wherein the R groups are different isused, the product will also contain cyclic phosphines wherein R groupsare different. Especially desirable phosphines for use in the process ofthe invention are those wherein the R group is hydrocarbon having notmore than 24 carbon atoms, preferably not more than 18 carbons, and forsome purposes not more than 8 carbon atoms. Examples of radicals beingsubstituted or interrupted by heteroatoms and occurring in well knownprimary phosphines are: F C,

The reaction of invention proceeds according to the following equation:

nRPH +2nA [RP(A) +nH- A A compound assumed to be thetetraphenylcyclotetraphosphinetetrasul-fide has been reported in theliterature (W. Kuchen and -H. Buchwald, Chem. Ber. 91, 2296, 1958). Inthis previous process at first the tetraphenylcyclotetraphosphine hasallegedly been prepared by reacting equimol-ar amounts ofphenylphosphine and phenyldichlorophosphine and has then been convertedinto the sulfur derivative by treating with sulfur. However,

it has been shown that aliphatically substituted cyclotetraphosphines(R=alkyl, cycloalkyl or aralkyl) cannot be converted by this method intothe corresponding tetrasulfides (K. Issleib and W. Seidel, Z. anorg.allg. Chem. 303, 155, 1960; Z. Naturforschung 15b, 267, 1960). Similarlyonly a compound assumed to be thetetraphenylcyclotetraphosphinetetraselenide (R=phenyl) has beendescribed in the literature until now. (H. C. Krauss and H. Jung. Z.Naturf. 15b, 545, 1960.) This selenide of the prior art was prepared inan analogous manner to the sulfide of the prior art.

Contrarily, primary organophosphines can be converted by the novelprocess, using a single reaction step, into the corresponding cyclicphosphine sulfides or selenides.

In carrying out the reaction, the reactants in a suitable stoichiometricproportion are mixed, whereafter the exothermic reaction starts atambient temperature. It is expedient to subsequently heat the reactionmixture for a short time at a higher temperature, e.g. 60-120 C. One canwork with or without a solvent. Suitable solvents are those which reactneither with the primary phosphine nor with sulfur or selenium, such asbenzene, toluene, xylene, methylchloride, ether, etc. The aromaticderivatives having the formula [Aryl PSJ can be worked up bycrystallization or sublimation, while the aliphatic derivatives havingthe formula [Alkyl PS1,, according to the number of carbon atoms andstructure of the radicals, often can be distilled under reducedpressure.

The products resulting from the process are liquid or solid, accordingto the organo groups which are present. They can be used as heattransferring liquids at high temperatures, lubricant additives forthermally highly stressed machine parts, hydraulics, agents fortextiles, anti-foamants, anti-oxidants, stabilizers, accelerators invulcanization, plasticizers, hydrophobing agents, flameproofing agents,active ingredients of pesticides such as insecticides and fungicides,and means for combatting undesired plant growth. The novel compoundshaving unsaturated and/or else reactive substituents are valuableintermediates for the preparation of polymers.

Example 1 A mixture of 11 g. of C H PH (0.1 mole) and 6.4 g. of sulfur(0.2 mole) in ml. of benzene is heated gradually up to 60 C. A vigorousreaction ensues with evolution of hydrogen sulfide. After stirring for30 minutes at room temperature, most of the benzene is distilled offunder reduced pressure. Then, ether is added and the solution cooledwith ice. There are obtained 9.5 g. (=68%) of [C H PSJ which melts afterrecrystallization in benzene at 148 C. (literature 150.5 C.; W. Kuchenand H. Buchwald, Chem. Ber. 91, 2296, 1958).

Analysis C H P S (420.4).Calc. percent: C, 51.42; H, 3.59; S, 22.87.Found percent: C, 52.12; H, 3.14; S, 23.07.

Example 2 Upon mixing 14.6 g. of n-C H PH (0. 1 mole) and 6.4 g. ofsulfur (0.2 mole) reaction occurs at room temperature with evolution ofhydrogen sulfide. In order to complete the reaction the mixture isheated at 100 C. for 1 hour. The distillation of the viscous liquidgives pure tetraoctylcyclotetraphosphine tetras-ulfide in a practicallyquantitative yield; B.P. 245-250 C./0.1 mm. n 1.5513.

Analysis C H 1 S (705.0).Calc. percent: C, 54.51; 28219472; S, 18.19.Found percent: C, 54.56; H, 9.76; S, The determination of the molecularweight in benzene gave 703 (average of 3 determinations).

l (0.2 mol) of pulverized red zene, there occurs an exothermic Example 3A mixtureof 5.4 g. (0.06 mole) of C H PH (a mixture of 95% isoandn-butylphosphine) and 3.84 g. of sulfur (0. 12 mole) in 50 ml. ofbenzene is gradually heated up to 80 0., thereby hydrogen sulfide isreleased. The fractional distillation of the solution yields 7.1 .g.(=97%) of tetrabutylcyclotetraphosphine tetrasulfide; B.P. 149-152"C./0.02 mm; M.P. 78- 82 C. 21 1.5919.

Analysis C H 'P 'S4(480.6).Calc. percent: C, 39.98; H, 7.55; S, 26.68.Found percent: C, 40.43; H, 7.61; S, 26.71.

The determination of the molecular weight in benzene gave 451 (averageof 3 determinations).

Example 4 On combination of 11 g. (0.1 mole) C H PH and 16 g.

selenium in 100 ml. of benreaction with a development of hydrogenselenide, so that the temperature'of the mixture risesto about 50 C. Themixture is heated on a refiux until no further significant amount ofhydrogen selenide is developed, which is the case after about 2 hours.After filtering off a small amount of the nonreacted selenium thesolvent is distilled off. 15 g. (80%) [C H PSeh are obtained. Afterrecrystallization from carbon disulfide/petroleum ether the compoundmelts at 7477 C. (Literature reference cited 7172 C.)

Analysis C H -P Se .-Calc. percent: C, 38.52; H, 2.70; P, 16.56; Se,42.22. Found percent: C, 40.26; H, 3.64; 'P, 17.01; Se, 38.93.

Example 5 fluxed. After one hour a clear solution is obtained. The

benzene is distilled off and a colorless viscous liquid remains whichcrystallizes after 3 days standing at room temperature. Yield 11.6 g.(100%); of tetra-n dodecylcyclotetraphosphine tetrasulfide; MJP. 30-32C.

The same compound is also obtained on working with out a solvent. A fewminutes after having mixed the reactants a vigorous exothermic reactionensues with the evolution of H 5. All the sulfur is dissolved and aclear viscous liquid is obtained which crystallizes after some time;M.P. 3032 C. The yield is quantitative.

Analysis C48H1OOP4S4 percent: C, 62.02; H, 10.84; S, 113.79. Foundpercent: C, 61.32; H, 10.40; S, 15.58.

Example 6 Upon mixing 9.3 g. (0.075 mole) of C H CH PH and 4.8 g. (0.15mole) of sulfur an exothermic reaction starts at room temperature withevolution of H 8. The reaction is completed by heating for one hour atC. A viscous liquid is obtained which crystallizes on cooling to 0 C.Yield 14.1 g. (100%) of [C H CH PS] M.P. 28 C.

What is claimed is: 1. A compound of the formula 5.Tetraisobutylcyclotetraphosphine tetrasulfide.

6. Tetra-n-dodecylcyclotetraphosphine tetrasulfide. 7. A process for,making compounds of the formula wherein R is selected from the classconsisting of alivphatic, cycloaliphatic and araliphatic radicals, A isselected from the class consisting of sulfur and selenium and n is 3 or4, comprising mixing at a temperature at which hydrogen sulfide orhydrogen selenide is given off a compound of the formula RPH wherein Ris as defined hereinabove with a material selected from the classconsisting of selenium and sulfur.

8. A process of claim 7 wherein the molar ratio of the primary phosphineto sulfur is about 1:2.

9. A process of claim 7 wherein the reaction is carried 2 out in thepresence of an inert solvent.

10. A process of claim 7 wherein ried out at a temperature in the rangeof 40 to C. 11. A process of claim 7 wherein R has not more than 24carbon atoms.

12. A process of claim 7 wherein R is alkyl hydrocarbon having not morethan 8 carbon atoms.

13. A process of claim 7 wherein R is aralkyl hydrocarbon having notmore than 8 carbon atoms.

References Cited Kohler et al., Chemische Berichte, vol. 10, page 807(1877).

TOBIAS E. LEVOW, Primary Examiner.

W. F. W. BELLAMY, Assistant Examiner.

the, reaction is car:

1. A COMPOUND OF THE FORMULA